Question

Consider the function represented by 9x+3y= 12 with x as the independent variable. How can this function bewritten using function notation?

Answer 1

If x is the independent variable, we have that y is the dependent variable.

Using function notation, let's say that y is our function, that is, y = f(x).

So we need to isolate the variable y in the equation:

$\begin{gathered} 9x+3y=12 \\ 3y=12-9x \\ y=\frac{12-9x}{3} \\ y=4-3x \end{gathered}$

So our function is:

$f(x)=-3x+4$